Lifting device



Jan Z@, 3956 BRASELMANN 2,731,842

- LIFTING DEVICE Filed Nov. 8, 1951 United States Patent Ofice 2,731,842 Patented Jan. 24, 1956 2,731,842 LIFTING DEVICE Ferdinand Braseimann, Ennepetal-Oberbauer, Germany, assignor to Firma Ferd. Braselmann, Ennepetai-Qberbauer, Germany Application November 8, 1951, Serial No. 255,466 Claims priority, application Germany November 9, 1950 11 Claims. (Cl. 74-141.5)

surrounding the shaft, ranged between said forked member is moved stepwise along the shaft.

The novel features which are considered as characteristic for the invention are set forth in appended claims. The invention itself, however, both the line C D of Fig. 4. Referring and first to Figs. 1 to 3, 1 denotes a substantially vertical shaft along which are displaceable a load-supporting forked member 2, a first clamping member 3, and a second clamping member 4. The forked member 2 is provided with an upper or first prong 6 and a lower or second prong 6' which are subprong 5 and the second. prong 6 have apertures sur- The vertical part 6" is provided h a load-supporting extension 6".

The first clamping member 3 and the second clamping member 4 are arranged between the prongs 6 and 6 of the forked member 2, and have apertures provided with tilted walls such as 4' which come into clamping contact with the shaft 1, similar to the tilted walls of the clamping members disclosed in the co-pending patent application Serial No. 226,043, filed May within the space defined member 2. A helical compression spring between the second clamping member 4 and the second prong 6 of 3 an having an inclined Wall on which one faces of the projection 20 slides. stood that the forked members urges the first clamping member tion. It should be noted that this is due not only to the the mutually engaging the recess 21.

The clamping members 3 and 4 have, respectively, peripheral portions 22 and 23 which are turned away from the vertical part 6" of the forked member 2 and are arranged one above the other, the peripheral portion 23 of the second clamping member having a slightly axis of the shaft 1 than of the side Thus it will be under- 2 supporting the load with recesses 24 and 25, which approximately cylindrical space 26 provided near the tip 27 duced so that the latter disclosed hereinafter.

in order to prevent a rotation of the clamping members 3 and 4 with respect to the shaft 1, forked end portions 9 engaging the vertical part 6 of the forked member 2 are provided on the clamping members.

Furthermore, earns 10 and 11 are laterally projecting from the first clamping member 3 and the first prong 6 of the forked member 2, respectively, the purpose of which will be more fully disclosed hereinafter.

The operation of this device is as follows:

If it is intended to lift the load supported by the extension 6 of the forked member 2 and indicated by dotted lines in Fig. the tip 27 of 21 preferably manu- 4. During the clamping member 4 is pressed upwards by the helical spring 5 thus combe repeated any up to the top end of the shaft 1.

6 of the forked member 2 near the vertical part 6" thereof. in order to facilitate this operation the cams 1t) and 11 are provided. The lever 7 is carefully moved downwards in order to slightly turn and thereby release the clamping member 3 from the clamping position thereof whereupon the clamping members 3, 4 and the forked member supporting the load are lowered a short distance after which the lever 7 is swung upwards in order to allow the first clamping member 3 to come again into clamping position. If it is desired to lower the load further, this cycle of operation is repeated as often as desired.

The point of abutment of the lever 7 against the second clamping member 4 has a slightly larger radial distance from the axis of the shaft 1 than the point of abutment of the lever 7 against the first clamping member 3. By this arrangement it is accomplished that the lever 7 during the upward and downward strokes thereof carries out very little or no displacement in the axial direction thereof with respect to the first clamping member 3 so that a force due to sliding of the shorter arm 27 of the lever 7 on the first clamping member 3 is avoided. However, this structure has the disadvantage that the length of the shorter arm 27 of the lever 7 must exceed a definite lower limit, thus limiting the lifting power of the manually operated device. This disadvantage is avoided in the second embodiment of the present invention more fully disclosed hereinafter.

If desired, the forked member 2 supporting the load could be made stationary and the shaft 1 could be moved by the ratchet-like operation of the clamping members 3 and 4.

Referring now to Figs. 4 and 5, showing a shaft 1, a forked member 2a, two clamping members 311, 4a and a helical spring 5 inserted between the lower prong 6a of the forked member 2a having the same functions as the corresponding parts of the embodiment shown in Figs. 1 to 3, it will be noted that the driving lever 17 is pivoted by the pivot 18 to the second clamping member 4a, and has an end portion 16 forming the shorter arm of the two-armed lever 17 and being designed as a lifting cam or eccentric having a small inclination.

roller 19 is pivoted freely at 30 to the peripheral portion of the first clamping member 3a. The lifting earn 16 of the two-armed lever 17 engages the roller 19 from below, the pivot 18 being arranged below and laterally displaced with respect to the point of contact between the cam 16 and the roller 19. It should be noted that in view of the slight inclination of the cam 16 the latter slides over a longer path on the roller 19 which, however, does not involve an increased friction since the roller 19 is loosely connected to the first clamping member 3a by the pivot 3% thereof. With the lifting device according to Figs. 4 and 5 loads of several tons weight can be lifted without difficulty by Y swinging the relatively short lever 17 downwards and upwards.

The vertical part 6a" of the forked member 2a is engaged by forked portions 9a of the clamping members 3a and 4a which have the same function as the corresponding portions of the embodiment shown in Figs. 1 to 3. However, instead of engaging the vertical part 6a" from the outside, the forked portions 9a could be designed so as to enter a gro ve provided in the vertical portion 6a". Furthermore, cams 10a and 110 are provided on the first clamping member 3a and the first prong 6a of the forked member 2a which serves the same purpose as the corresponding portions of the embodiment shown in Figs. 1 to 3.

Also in the embodiment according to Figs. 4 and S the forked member 2a could be the stationary part and the shaft 1 the movable part, if desired.

It should be noted that in both of the embodiments shown in the drawing, spring 5 urges the lower clamping member upwardly towards the upper clamping memher, and when the lever means shown in the respective embodiments is in an inoperative position, that is, when no lifting force is exerted thereby on the upper clamping member, it will be evident that spring 5 will press the lower clamping member against the upper clamping member, the clamping members in this condition being in rest position, as hereinafter referred to in the claims.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of lifting devices differing from the types described above.

While the invention has been illustrated and described as embodied in a jack having a forked member and two clamping members engaging a shaft, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be secured by Letters Patent is:

l. A jack, comprising in combination, an elongated shaft; a forked member having a first prong and a second prong, each of said prongs having an aperture surrounding said shaft; a first clamping member having an aperture surrounding said shaft; a second clamping member having an aperture surrounding said shaft, said clamping members being arranged between said prongs of said forked member, said first prong of said forked member being arranged adjacent to said first clamping member; releasable means for force-locking said first prong of said forked member with said first clamping member; resilient means inserted between said second clamping member and said second prong of said forked member; and means for exerting an oscillating force on said clamping members whereby said clamping members are alternately clamped to said shaft and said forked member is moved step-wise along said shaft.

2. A jack, comprising in combination, an elongated substantially vertical shaft; a load-supporting forked member having a first prong and a second prong, each of said prongs having an aperture surrounding said shaft; 21 first clamping member having an aperture surrounding said shaft; a second clamping member having an aperture surrounding said shaft, said clamping members being ar ranged between said prongs of said forked member, said first prong of said forked member being arranged adjacent to said first clamping member; means for suspending said first prong of said forked member from one side of said first clamping member so as to press the same into clamping position; resilient means inserted between said second clamping member and said second prong of said forked member; and means for exerting an oscillating force on said clamping members whereby said clamping members are alternately clamped to said shaft and said forked member is moved stepwise along said shaft.

3. A jack, comprising in combination, a substantially vertical elongated shaft; a forked member having a substantially horizontal first prong, a substantially horizontal second prong, and a substantially vertical part connecting said horizontal prongs, each, of said prongs having an aperture surrounding said shaft; 2. first clamping member having an aperture surrounding said shaft; a second clamping member having an aperture surrounding said shaft, said clamping members being arranged between said prongs of said forked member and having each a peripheral portion turned away from said vertical part of said forked m stepwise along said shaft.

4. A jack, comprising in combination, a substantially vertical elongated shaft; a forked member having a substantially horizontal first prong, a substantially horizontal second prong, and a substantially vertical part connect- 5. A jack, comprising in combination, a substantially vertical elongated shaft; a forked member having a substantially horizontal first prong, a substantially horizontal second prong, and a substantially vertical part connecting said horizontal prongs, each ing member having an aperture surrounding said shaft, said clamping members belng arranged between said forked member, said pair of cams allowing a lever to be inserted between them in order to release said clamping members from the clamping positions thereof.

7. A ja shaft; a forked being arranged ad acent to said first clamping member; releasable means for force-locking said first prong of said forked member with said first clamping member; resilient means inserted between said second clamping member 8. A jack, comprising in combination, vertical elongated shaft; a forked member having a substantially horizontal first prong, a substantially horizontal second prong, and a substantially vertical part connecting said horizontal prongs, each of said prongs having a substantially member so as to press the same into clamping position; resilient means inserted between said second clamping 9. A jack, comprising in combination, a substantially vertical elongated shaft; a forked member having a substantially horizontal first prong, a substantially horizontal second prong, and a substantially vertical part connecting said horizontal prongs, each of said prongs having an aperture surrounding said shaft; a first clamping member having an aperture surrounding said shaft; a second clamping member having an aperture surrounding said shaft, said clamping members being arranged lying against each other in rest position between said prongs of said forked member and having each a peripheral portion turned away from said vertical part of said forked member, said peripheral portions being arranged one above the other, said first prong of said forked member being arranged adjacent to said first clamping member; means for suspending said first prong of said forked member from said peripheral portion of said first clamping member so as to press the same into clamping position; resilient means inserted between said second clamping member and said second prong of said forked member urging said second clamping member against said first clamping member; a roller pivoted to said peripheral portion of said first clamping member; a lever pivoted to said peripheral portion of said second clamping member and having an end portion cooperating with said roller i whereby by imparting a pivotal motion to said lever an oscillating force is exerted alternately on said peripheral portions of said clamping members so that the same are alternately clamped to said shaft and said forked member is moved step-wise along said shaft; and a pair of cams arranged, respectively, one above the other on said first clamping member and said first prong of said forked member, said pair of cams allowing a lever to be inserted between them in order to release said clamping members from the clamping positions thereof.

10. A jack, comprising in combination, a substantially vertical elongated shaft; a forked member having a substantially horizontal first prong, a substantially horizontal second prong, and a substantially vertical part connecting said horizontal prongs, each of said prongs having an aperture surrounding said shaft; a first clamping member having an aperture surrounding said shaft; a second clamping member having an aperture surrounding said shaft; 21 second clamping member having an aperture surrounding said shaft, said clamping members being arranged lying against each other in rest position between said prongs of said forked member and having each a peripheral portion turned away from said vertical part of said forked member, said peripheral portions being arranged one above the other, said first prong of said forked member being arranged adjacent to said first clamping member; means for suspending said first prong of said forked member from said peripheral portion of said first clamping member so as to press the same into clamping position; resilient means inserted between said second clamping member and said second prong of said forked member urging said second clamping member against said first clamping member; a roller pivoted to said peripheral portion of said first clamping member; a two-armed lever pivoted to said peripheral portion of said second clamping member; an end portion forming one arm of said two-armed lever, said end portion being designed as a lifting cam being in contact with said roller,

the pivot of said lever being arranged below and laterally displaced with respect to the point of contact between said roller and said lifting cam, whereby while imparting a pivotal motion to said lever an oscillating force is exerted alternately on said peripheral portions of said clamping members so that the same are alternately clamped to said shaft and said forked member is moved stepwise along said shaft; and a pair of cams arranged, respectively-one above the other on said first clamping member and said first prong of said forked member, said pair of cams allowing a lever to be inserted between them in order to release said clamping members from the clamping positions thereof.

11. A jack, comprising in combination, a substantially vertical elongated shaft; a forked member having a substantially horizontal first prong, a substantially horizontal second prong, and a substantially vertical part connecting said horizontal prongs, each of said prongs having an aperture surrounding said shaft; a first clamping member having an aperture surrounding said shaft; a second clamping member having an aperture surrounding said shaft, said clamping members being arranged lying against each other in rest position between said prongs of said forked member and having each a peripheral portion turned away from said vertical part of said forked member, said peripheral portions being arranged one above the other, said first prong of said forked member being arranged adjacent to said first clamping member; means for suspending-said first prong of said forked member from said peripheral portion of said first clamping mem ber so as to press the same into clamping position; resilient means inserted between said second clamping member and said second prong of said forked member urging said second clamping member against said first clamping member; a roller pivoted to said peripheral portion of said first clamping member; a two-armed lever pivoted to said peripheral portion of said second clamping member; an end portion forming one arm of said two-armed lever, said end portion being designed as a lifting cam being in contact with said roller, the pivot of said lever being arranged below and laterally displaced with respect to the point of contact between said roller and said lifting cam, whereby while imparting a pivotal motion to said lever an oscillating force is exerted alternately on said peripheral portions of said clamping members so that the same are alternately clamped to said shaft and said forked member is moved stepwise along said shaft; and a pair of cams projecting laterally from said first clamping member and said first prong of said forked members, said cams being arranged one above the other and allowing a lever to be inserted between them in order to release said clamping members from the clamping positions thereof.

References Cited in the file of this patent UNITED STATES PATENTS 2,227,397 Lucker Dec. 31, 1940 2,242,431 Lucker May 20, 1941 2,305,238 Coates Dec. 15, 1942 2,513,978 White July 4, 1950 2,534,837 Crewe Dec. 19, 1950 2,537,839 Lord Jan. 9, 1951 

